Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

follows UTC+07:00, which is 7 hours ahead of

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

. The local mean time in

Bangkok Bangkok, officially known in Thai language, Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estim ...

was originally UTC+06:42:04. Thailand used this local mean time until 1920, when it changed to Indochina Time, UTC+07:00; ICT is used all year round as Thailand never observed

daylight saving time Daylight saving time (DST), also referred to as daylight savings time, daylight time (Daylight saving time in the United States, United States and Daylight saving time in Canada, Canada), or summer time (British Summer Time, United Kingdom, ...

. Thailand shares the same time zone with

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...

Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an States and territories of Australia#External territories, Australian external territory in the Indian Ocean comprising the island of the same name. It is about south o ...

, and

Western Indonesia Western Indonesia is one of the two main geographical Regions of Indonesia, regions of Indonesia, the other being Eastern Indonesia. It consists of 21 provinces in Sumatra, Java, and Kalimantan. Western Indonesia Time (''Waktu Indonesia Barat'', W ...

, as well as parts of Russia.

History

* Prior to 1 January 1901, locations in

Siam Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

with an

astronomical observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...

would adopt

local mean time Local mean time (LMT) is a form of solar time that corrects the variations of local apparent time, forming a uniform time scale at a specific longitude. This measurement of time was used for everyday use during the 19th century before time zones ...

based on the observatory's geographic position.

Chiang Mai Province Chiang Mai is the largest Provinces of Thailand, province (''changwat'') of Thailand by area. It lies in Northern Thailand#Regional classification of northern Thailand, upper northern Thailand and has a population of 1.78 million people. It ...

and two other provinces each had an observatory, hence, each province had its own distinct local mean time, with minutes of difference between the three locations. * On 1 April 1920, the mean time of the

105th meridian east The meridian 105° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. Under mean solar time represents the offset of ...

(passing through Ubon Ratchathani Province) was adopted by

as the new

standard time Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than a local mean time standard. Generally, standard time agrees with the local mean time at some meridian that passes through the r ...

. The mean time of the 105th meridian is 7 hours ahead of

Greenwich Mean Time Greenwich Mean Time (GMT) is the local mean time at the Royal Observatory, Greenwich, Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being ...

(i.e., local mean time at the

Greenwich Royal Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

). * In July 2001, Thailand announced its intention of moving its time forward one hour, to align with both

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

and more importantly with

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

, Central Indonesia, and

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

, i.e., UTC+08:00. This was met with much criticism and resistance and the plan was withdrawn.

Standardisation of time in Thailand

Thailand declared on 16 March 1920 that people would move their clocks ahead by 17 minutes, 56 seconds on 31 March 1920 to match the time in use in

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. The time was switched on 1 April 1920 at 00:00 (old time) to 00:17:56 (new time).

Timekeeper

On 1 January 1990, the

Cabinet of Thailand The cabinet of Thailand (formally, the Council of Ministers of Thailand; ; is a body composed of thirty-five of the most senior members of the government of the Kingdom of Thailand. The Cabinet (government), cabinet is the primary organ of the ...

appointed the

Royal Thai Navy The Royal Thai Navy (Abbreviation, Abrv: RTN, ทร.; , ) is the Navy, naval warfare force of Thailand. Established in 1906, it was modernised by the Admiral Prince Abhakara Kiartiwongse (1880–1923) who is known as the father of the Royal N ...

as the official timekeeper for Thailand. Thai Standard Time is derived from five

atomic clock An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betwee ...

s maintained by the Royal Thai Navy.

References

External links

{{Asia topic, Time in

Time in Southeast Asia

History

Standardisation of time in Thailand

Timekeeper

See also

References

External links